Coeur d'Alene Lake encompasses 49.8 square miles at its normal full-pool elevation (2,128 feet above sea level), with a maximum water depth of 209 feet. Its principal tributaries are the St. Joe's River and the Coeur d'Alene River. It flows out to form the Spokane River. Coeur d'Alene Lake is a natural lake but it's elevation is controlled by the Post Falls Dam. A large volume of metal-contaminated sediment has been deposited on the Lake bottom.

The Coeur d'Alene Basin (OU 3) Record of Decision does not include cleanup actions for the Coeur d'Alene Lake. State, tribal, federal, and local governments are currently in the process of implementing a Lake Management Plan outside of the Superfund process using separate legal authorities.